CVE-2024-26956: Linux kernel · nilfs2: fix failure to detect DAT corruption in btree and direct mappings
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 5.4.0-1128.138~18.04.1 : patch Linux kernel soon.
Data as of 28 Oct 2026, 10:59 UTC
- Patch
- Available – fixed in 5.4.0-1128.138~18.04.1, 5.4.0-1133.140~18.04.1, 5.4.0-1132.141~18.04.1 +62
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 1 May 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
- ubuntu.com/security/notices/USN-6816-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6817-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6817-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6817-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-6878-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6896-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6898-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6896-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6898-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6896-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-6898-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-6896-4 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-ibmpkg:deb/ubuntu/linux-ibm?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix failure to detect DAT corruption in btree and direct mappings Patch series "nilfs2: fix kernel bug at submit_bh_wbc()". This resolves a kernel BUG reported by syzbot. Since there are two flaws involved, I've made each one a separate patch. The first patch alone resolves the syzbot-reported bug, but I think both fixes should be sent to stable, so I've tagged them as such. This patch (of 2): Syzbot has reported a kernel bug in submit_bh_wbc() when writing file data to a nilfs2 file system whose metadata is corrupted. There are two flaws involved in this issue. The first flaw is that when nilfs_get_block() locates a data block using btree or direct mapping, if the disk address translation routine nilfs_dat_translate() fails with internal code -ENOENT due to DAT metadata corruption, it can be passed back to nilfs_get_block(). This causes nilfs_get_block() to misidentify an existing block as non-existent, causing both data block lookup and insertion to fail inconsistently. The second flaw is that nilfs_get_block() returns a successful status in this inconsistent state. This causes the caller __block_write_begin_int() or others to request a read even though the buffer is not mapped, resulting in a BUG_ON check for the BH_Mapped flag in submit_bh_wbc() failing. This fixes the first issue by changing the return value to code -EINVAL when a conversion using DAT fails with code -ENOENT, avoiding the conflicting condition that leads to the kernel bug described above. Here, code -EINVAL indicates that metadata corruption was detected during the block lookup, which will be properly handled as a file system error and converted to -EIO when passing through the nilfs2 bmap layer.
References
- ubuntu.com/security/CVE-2024-26956 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2024-26956 (opens in a new tab)
- git.kernel.org/linus/f2f26b4a84a0ef41791bd2d70861c8eac748f4ba (opens in a new tab)
- git.kernel.org/stable/c/b67189690eb4b7ecc84ae16fa1e880e0123eaa35 (opens in a new tab)
- git.kernel.org/stable/c/9cbe1ad5f4354f4df1445e5f4883983328cd6d8e (opens in a new tab)
- git.kernel.org/stable/c/c3b5c5c31e723b568f83d8cafab8629d9d830ffb (opens in a new tab)
- git.kernel.org/stable/c/2e2619ff5d0def4bb6c2037a32a6eaa28dd95c84 (opens in a new tab)
- git.kernel.org/stable/c/46b832e09d43b394ac0f6d9485d2b1a06593f0b7 (opens in a new tab)
- git.kernel.org/stable/c/f69e81396aea66304d214f175aa371f1b5578862 (opens in a new tab)
- git.kernel.org/stable/c/a8e4d098de1c0f4c5c1f2ed4633a860f0da6d713 (opens in a new tab)
- git.kernel.org/stable/c/82827ca21e7c8a91384c5baa656f78a5adfa4ab4 (opens in a new tab)
- git.kernel.org/stable/c/f2f26b4a84a0ef41791bd2d70861c8eac748f4ba (opens in a new tab)
- ubuntu.com/security/notices/USN-6816-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6817-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6817-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6817-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-6878-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6896-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6898-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6896-2 (opens in a new tab)